1、A mail transfer agent such as Sendmail 8.7 or later.
一個郵件傳輸代理，比如Sendmail 8.7或者更高的版本。

2、E-mail is sent via mail transfer agents, mail delivery agents, and mail user agents.
電子郵件通過郵件傳輸代理、郵件發(fā)送代理及郵件用戶代理發(fā)送。

3、I will explain for you. The other two are mail transfer and demand draft.
我來跟您解釋，其余兩種是信匯和票匯。

mail transfer翻譯